Human body cells die for one of two reasons. They either suffer some sort of environmental trauma that causes cell death suddenly and accidentally, or they kill themselves off in a planned, controlled process known as apoptosis. The latter scenario, it turns out, is very important to healthy human development and life.

Unplanned Cell Death

Cells die in an unplanned manner when exposed to a variety of harmful environmental agents. These include both chemical and physical events, or “insults,” and range from radiation, heat, toxic substances, bodily trauma or injury and lack of oxygen. Injured cells swell up, burst, spill their contents and cause surrounding cells to react defensively. This often involves inflammation and the calling in of specialized immune cells to deal with cleanup and isolation of the damaged tissue.

Cell Apoptosis

Apoptosis is the opposite of unplanned cell death: it is a carefully executed death of a certain cell, sometimes known as “programmed cell death” or “cell suicide.” This ability to die on command is encoded in the human genome and that of other organisms as well. According to the College of St. Benedict and St. John’s University, apoptosis is used to keep the number of cells in an organism at a certain specified level, to allow the organism to change rapidly such as during embryonic development and to kill off harmful cells.

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Cell Remains

Once the cell is targeted for suicide, its genes controlling the breakdown process become activated. It condenses and breaks down its nucleus, DNA and cytoplasm. Immune cells called phagocytes, whose job it is to remove unwanted material from the organism, envelop the remaining cell material and break it down. Specialized enzymes called caspases also aid in the breakdown process, helping to disassemble the cell in a controlled way.

Cancer Research

When cells do not reliably undergo apoptosis, problems such as cancer can result. Cancer is a process of uncontrolled growth of certain cells in the body of affected individuals. According to Siva Kumar Kolluri of Oregon State University, certain proteins regulate apoptosis, but when they fail to function as they should, cells do not die. If, however, researchers can learn to trigger apoptosis in cancer cells but allow normal cells to continue growing, they might be able to fight it more effectively.